US3516831A - Multicolor photographic elements containing both 4-equivalent and 2-equivalent color-forming couplers - Google Patents

Description

United States Patent MULTICOLOR PHOTOGRAPHIC ELEMENTS CON- TAINING BOTH 4-EQUIVALENT AND Z-EQUIV- ALENT COLOR-FORMING COUPLERS Wilfred L. Wolf and Clark Beckett, Rochester, N.Y., as-

signors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Apr. 27, 1967, Ser. No. 634,104

Int. Cl. G03c 1/76 U.S. Cl. 96-74 14 Claims ABSTRACT OF THE DISCLOSURE Multicolor photographic elements which contain double-coated differentially color sensitive color-forming units in which each color-forming unit contains a faster silver halide emulsion layer that receives light image exposure before a slower silver halide emulsion layer have increased photographic speed and improved image definition when an appropriate 4-equivalent color-forming coupler is incorporated in the faster emulsion layer and an appropriate 2-equivalent color-forming coupler is incorporated in the slower emulsion layer of at least the first color-forming unit in the element to receive exposing light.

This invention relates to color photography and to improved multicolor, multiplayer photographic elements for color photography.

Multicolor, multilayer photographic elements are well-known in the art of color photography. Usually these materials have three selectively sensitized emulsion layers coated on one side of a single support. For example, the

outermost layer is generally blue-sensitive. The next layer is generally green-sensitive and the layer adjacent to the support is generally red-sensitive. Between the blue-sensitive and green-sensitive layers, a bleachable yellow-colored filter layer is often used for absorbing blue radiation which may be transmitted through the blue-sensitive layer. The multilayer coatings can also have other interlayers for specialized purposes. Such multilayer materials have been previously described in the prior art such as Mannes et a1. U.S. Pat. 2,252,798, issued Aug. 19, 1941. It is known to replace the single differentially sensitized layers for recording each of the primary color lights as described above with doublecoated differentially-sensitive color-forming units. Usually each of the color-forming units comprises two lightsensitive emulsion layers that are sensitive to substantially the same primary color region (e.g., blue, green or red) of the visible spectrum. Other arrangements of the sensitive layers are also known. Usually the bluesensitive layer, the green-sensitized layer and the redsensitized layer are used to produce the yellow dye image, magenta dye image and the cyan dye image, respectively. Open-chain, pyrazolone and phenolic (and naphtholic) couplers are usually used for forming the yellow, magenta and cyan dye images, respectively. The couplers are incorporated in the appropriately sensitized emulsion layer of the photographic materials.

Conventional color-forming coupler are 4-equivalent, that is, they require the development of the four molecules of silver halide in order to form one molecule of dye. Two-equivalent couplers require the development of two molecules of silver halide to bring about the formation of one molecule of dye. Two-equivalent couplers are very desirable for color photography since only onehalf the usual amount of silver halide is needed and the light-sensitive coatings can thus be made thinner.

We have found that when double-coated dilferentially color sensitive units (segments) of the type described in Patented June 23, 197Q German Pat. 1,121,470 are coated wherein 2-equivalent color-forming couplers are utilized in all layers, that the expected increase in sharpness is obtained, however, there is a substantial loss in photographic speed.

We have found furthermore that when each of these double-coated differentially color sensitive layers contains a 4-equivalent color-forming coupler too much light is scattered in these necessary thick layers which decrease sharpness.

Photographic elements are desired which have both increased sharpness as well as increased speed.

It is therefore an object of our invention to provide novel incorporated coupler double-coated differentially sensitive color-forming units for use in color photographic elements that exhibit improved photographic characteristics.

Another object of our invention is to provide novel multilayer, multicolor photographic elements that contain incoporated couplers and which contain one or more double-coated differentially sensitive color-forming units which exhibit substantial increases in photographic speed and substantial improvement in recorded image sharpness.

Another object of our invention is to provide a novel subtractive color photograpic material of increased speed and improved image definition which contains incorporated color-forming couplers and which uses a doublecoated differentially sensitive blue-sensitive yellow-forming unit as the outermost image recording layers of the element and a double-coated differentially sensitive greensensitized unit as the next to the outermost image recording layers.

Still another object of our invention is a novel method for substantially improving the speed and image definition in an incorporated coupler containing multicolor photographic element by using our novel double-coated diiferentially color sensitive units.

These and still other objects will be apparent from consideration of the following specification and claims.

These and other objects are accomplished according to our invention by the use of our novel double-coated differentially color sensitive color-forming units, each unit comprising a first hydrophilic colloid silver halide emulsion layer containing a substantially colorless Z-equivalent color-forming coupler and a second hydrophilic colloid silver halide emulsion layer containing a 4-equivalent color-forming coupler such that the second layer has a higher photographic speed than the first layer. The layers of each color-forming unit used in our photographic materials are coated so that the faster hydrophilic colloid silver halide emulsion layer containing the 4-equivalent coupler is preferably coated so that the image exposing light passes through it before the hydrophilic colloid silver halide emulsion layer containing the 2-equivalent coupler. Our multicolor photographic elements are comprised of superimposed differently color-sensitive different colorforming hydrophilic colloid-silver halide emulsion strata with at least one stratum comprising one of our colorforming units, preferably arranged so that image exposing light passes through our unit before a second stratum and a third stratum and when a second of our color-forming units is used preferably this forms the second stratum, and when a third of our color-forming units is used this forms the third stratum.

Hydrophilic colloids used to advantage include gelatin, colloidal alubumin, a cellulose derivative, or a synthetic resin, for instance, a polyvinyl compound. Some colloids which may be used are polyvinyl alcohol or a hydrolyzed polyvinyl acetate as described in Lowe U.S. Pat. 2,286,- 215, issued June 16, 1942; a far hydrolyzed cellulose ester, such as cellulose acetate hydrolyzed to an acetyl content of 1926% as described in Lowe et a1. U.S. Pat.

2,327,808, issued Aug. 24, 1943; a water-soluble ethanolamine cellulose acetate as described in Yutzy U.S. 2,322,- 085, issued June 15, 1943; a polyacrylamide having a combined acrylamide content of 3060% and a specific viscosity of O.251.5 on an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe et al. U.S. Pat. 2,541,474, issued Feb. 13, 1951; zein as described in Lowe U.S. Pat. 2,563,791, issued Aug. 7, 1951, a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh et al. U.S. Pat. 2,768,154, issued Oct. 23, 1956, or containing cyano-acetyl groups, such as the vinyl alcohol-vinyl cyano-acetate copolymer as described in Unruh et al. U.S. Pat. 2,808,331, issued Oct. 1, 1957; or a polymeric material which results from polymerizing a protein or a saturated acylated protein with a monomer having a vinyl group as described in Illingsworth et al. U.S. Pat. 2,852,- 382, issued Sept. 16, 1958.

Any of the photographic silver halide emulsions, e.g., silver bromide, silver bromoiodide, silver chloride, silver chlorobromide, silver bromochloroiodide, etc, used in photography can be used to advantage in our photographic materials.

The emulsions used in the photographic element of our invention can be chemically sensitized by any of the accepted procedures. The emulsions can be digested with naturally active gelatin, or sulfur compounds can be added, such as those described in Sheppard U.S. Pat. 1,574,944, issued Mar. 2, 1926; Sheppard et al. U.S. Pat. 1,623,499, issued Apr. 5, 1927; and Sheppard et al. U.S. Pat. 2,410,689, issued Nov. 5, 1946.

The emulsions can also be treated with salts of the noble metals, such as ruthenium, rhodium, palladium, iridium and platinum, as described in Smith et al. U.S. Pat. 2,448,060, issued Aug. 31, 1948 and as described in Trivelli et al. U.S. Pats. 2,566,245 and 2,566,263, both issued Aug. 28, 1951.

The emulsions can also be optically sensitized with cyanine and merocyanine dyes, such as those described in Brooker U.S. Pats. 1,846,301 and 1,846,302, both issued Feb. 23, 1932; and 1,942,854, issued Jan. 9, 1934; White U.S. Pat. 1,990,507, issued Feb. 12, 1935; Brooker and White U.S. Pats. 2,112,140, issued Mar. 22, 1938; 2,165,- 338, issued July 11, 1939; 2,493,747, issued Jan. 1950; and 2,739,964, issued Mar. 27, 1956; Brooker et al. U.S. Pat. 2,493,748, issued Jan. 10, 1950; Sprague U.S. Pats. 2,503,776, issued Apr. 11, 1950, and 2,519,001, issued Aug. 15, 1950; Heseltine et al. U.S. Pat. 2,666,761, issued Jan. 19, 1954; Heseltine U.S. Pat. 2,734,900, issued Feb. 14, 1956; VanLare U.S. Pat. 2,739,149, issued Mar. 20, 1956; and Kodak Limited British 450,958, accepted July 15, 1936.

The emulsions may also contain speed-increasing compounds of the quaternary ammonium type of Carroll U.S. Pat. 2,271,623, issued Feb. 3, 1942; Carroll et al. U.S. Pat. 2,288,226, issued June 30, 1942; and Carroll et al. U.S. Pat. 2,334,864, issued Nov. 23, 1943; and the polyethylene glycol type of Carroll et al. U.S. Pat. 2,708,162, issued May 10, 1955.

The emulsions can also be chemically sensitized with gold salts as described in Waller et al. U.S. Pat. 2,399,803, issued Apr. 23, 1946, or stabilized with gold salts as described in Damschroder U.S. Pat. 2,597,856, issued May 27, 1952; and Yutzy et al. U.S. Pat. 2,597,915, issued May 27, 1942. Suitable compounds are potassium chloroaurite, potassium aurithiocyanate, potassium chloroaurate, a ric trichloride and 2-aurosulfobenzothiazole methochlon e.

The above-described emulsions can be coated on a wide variety of photographic emulsion supports. Typical supports include cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film, polyethylene film, polypropylene film, and related films of resinous materials, as well as paper, glass and others.

The hydrophilic colloid silver halide emulsions used in the layers of one of our novel color-forming units are advantageously made sensitive to substantially the same primary color region of the visible spectrum by using the appropriate optical sensitizing dyes where optical sensitization is required. The hydrophilic colloid layer containing the incorporated 4-equivalent coupler is made faster than the hydrophilic colloid silver halide emulsion layer containing the 2-equivalent coupler so that the faster emulsion has a speed that is from about .2 to about 1.0 log exposure faster than the other emulsion in the color-forming unit. It is advantageous to have the speed relationship such that the sensitometric curve (curve relating developed image density vs. the log exposure) of the two emulsion layers in a given color-forming unit together produce a smooth composite curve having the desired characteristics. The methods used to determine the optimum speed relationship between the two emulsions are well-known in the art and need not be discussed further herein. Obviously the color-forming layers and/or color-forming units in a given photographic element are advantageously made so that their sensitometric curves have the relationship required to reproduce a neutral scale as well as the color scales from the minimum density to the maximum density. Methods for doing this are wellknown in the art and need not be discussed further. Although photographic speeds of our color-forming layers and color-forming units may vary over a Wide range, it is usually advantageous to make their speeds as high as possible especially in the elements that are to be used in photographic cameras.

Any of the well-known 4-equivalent and Z-equivalent open-chain active methylene containing couplers are used to advantage in our yellow-image-forming units. These 4-equivalent couplers include the cyanoacetyl couplers (such as, the cyanoacetylcoumarone couplers, the cyanoacetylbenzoyl couplers, the heterocyclicacetonitrile couplers, etc.), the open-chain ketomethylene couplers, such as, the acylacetyl couplers (e.g., the acylacetanilide coupiers, the acylacetamide couplers, etc.). The acylacetanilide couplers include the alkoylacetanilide couplers, the aroylacetanilide couplers, the pivalylacetanilide couplers, etc. The acylacetamide couplers include the alkoylacetamide couplers, the aroylacetamide couplers, the pivalylacetamide couplers, etc.

These 4-equivalent open-chain couplers include those represented advantageously by the formula:

R O CHzX wherein R represents an alkyl group (substituted or not), an aromatic group (substituted or not), a heterocyclic group (substituted or not), etc.; and X represents the cyano group, a carbamyl group (substituted or not), etc. Usually R and/or X contains substituents which ballast the coupler and make it nonditfusing in hydrophilic colloid layers. A large variety of ballasting groups are very well-known in the art. When desired, the ballasting groups are provided with solubilizing groups.

Typical 4-equivalent yellow-forming couplers include the following:

( 1 N-amyl-p-benzoylacetaminobenzenesulfonate (2) N-(4-anisoylacetaminobenzenesulfonyl)-N-benzylm-toluidine (3 N- (4-benzoylaceta-minobenzenesulfonyl) -N-benzylm-toluidine.

(4) N- (4-benzoylacetaminobenzenesulfonyl) -N-n-amylp-toluidine 5 N- (4-benzoylacetaminobenzenesulfonyl) -N-benzylaniline (6) w- (p-benzoylbenzoyl) acetanilide (7) w-b enzoylacet-2,5 -dichloro anilide (8) w-benzoyl-p-sec.-amylacetanilide (9) N,N'-di w-benzoylacetyl -p-phenylenediamine (10) N,N'-di-(acetoacetamino)-dipheny1 (11) u-{3-[a-(2,4-di-tert.-amy1phenoxy)butyramido] benzoyl}-2-methoxyacetanilide (12) Ot-{3- oc- (2,4-di-tert.-amylphenoxy) acetamido] benzoyl}-2-methoxyacetanilide (13) 4,4-di-( acetoacetamino -3 ,3 -dimethyldipheny1 (14) p,p'-Diacetoacetamino diphenylmethane 15 Ethyl-p-benzoylacetaminobenzenesulfonate (16) Nonyl-p-benzoylacetaminobenzenesulfonate (17) N-phenyl-N'- (p-acetoacetaminophenyl) urea 18) n-Propyl-p-benzoylacetaminobenzenesulfonate acetoacetpiperidide 19) w-b enzoylacetpiperidide (20) N (w-benzoylacetyl) 1,2,3 ,5 -tetrahydroquinoline (21 N w-benzoylacetyl) morpholine The Z-equivalent yellow-forming couplers are derived from the general types of parent 4-equivalent couplers by replacing one of the two hydrogens on the alpha-carbon (i.e., methylene) with any nonchromophoric coupling off group including groups such as the fluorine atom, the chlorine atom, an acyloxy group, a cyclooxy group and a thiocyano group. Typical 2-equivalent couplers used to advantage included the alpha-fluoro couplers of U.S. Patent 3,277,155, the oc-ChlOIO couplers of U.S. Pat. 2,778,- 658, the a-thiocyano couplers of U.S. Pat. 3,253,924, the u-acyloxy couplers of Loria U.S. patent application 477,- 353, filed July 26, 1965, now U.S. Pat. 3,447,928, the a-CYCIOOXY couplers of Loria U.S. patent application 469,- 887, now U.S. Pat. 3,408,194, filed July 6, 1965, and u-alkthio, a-arylthio, and a-alkoxy couplers of the type shown in Whitmore et a1. U.S. Pat. 3,227,550.

The Z-equivalent open-chain yellow-forming couplers include those represented by the formula:

(II) X ll R-O- LEE-Y wherein R and X are as described previously; Y is a coupling 01f group, such as, the chlorine atom, the fluorine atom, the thiocyano group, an acyloxy group [e.g., an alkoyloxy group (substituted or not), an aroyloxy group (substituted or not), a heterocycloyloxy group (substituted or not), etc., in which the groups are substituted with a wide variety of well-known groups and also a group in which R and X are as described previously], and a cyclooxy group [e.g., an aryloxy group (e.g., a phenoxy group, a naphthoxy group), a heterocycloxy group (e.g., a pyridinyloxy group, a tetrahydropyranyloxy group, a tetrahydroquinolyloxy group, etc.)], an alkoxy group, alkthio group and an arylthio group in which these groups are advantageously substituted with a wide variety of well-known groups and also a R-Pl-CH-O- I group in which R and X are as defined previously.

Typical illustrative examples of Z-equivalent yellowfor-ming couplers include the following:

(1 4- (u-2'-methoxybenzoyl-a-chloroacetamido) -3"- (4"'-tert.-amylphenoxy) benzanilide (2) a-o-Methoxybenzoyl-u-chloro-4- [a- (2,4-di-tertamylphenoxy) -n-butyramido] -acet anilide (3) oc-{3- [oz- 2,4-di-tert-amylphenoxy) butyramido] benzoyl}-a-fiuoro-2-methoxyacetanilide (4) oc-FIUOIO-oc-piVfilYl-S- [7- 2,4-di-tert-amylphenoxy) butyramido] -2-chloroacetanilide (5 a-AcetoXy-a-{3- ['y- (2,4-di-tert-amylphenoxy) butyramido] benzoyl}-2-methoxyacetanilide (6) a-Benzoyl-aoa- (2,4-di-n-amylphenoxy) acetoxy] -2- methoxyacetanilide (7) ot-Pivalyl-a-stearoyloxy-4-sulfamylacetanilide (8) a-Pivalyl-ococ- (3-pentadecylphenoxy) acetoxy] 3 ,5 -dicarboxyacetanilide (9) a-AcetoXy-a-{3- a- (2,4-di-tert-amylphenoxy) butyramido] benzoyl}-2-methoxyacetanilide 10) a- 3-dodecanamidobenzoyl -a-octanoyloxy-2- methoxyacetanilide 11 a-{3- ['y- (2,4-di-tert-amylphenoxy butyramido] benzoyl}-a (4-nitrophenoxy -2-methoxyacetanilide 12) 00- [4- (N-methyl-N-octadecylsulfamyl) phenoxy] u-pivalyl-4-sulfoacetanilide potassium salt 13 a-pivalyl-a- (4-sulfophenoxy-4- (N-methyl-N- octadecyl-sulfamyl acetanilide potassium salt 14) oz- [4- (4-hydroxyphenylsulfonyl) phenoxy] -apivalyl-Z-chloro-S- [*y- (2,4-di-tert-amylphenoxy) butyramido] acetanilide (15) 4,4-bis [u-pivalyl-u-{2-chl0ro-5- ['y- (2,4-di-tertamylphenoxy )butyramido] phenylcarbamyl} methoxy] -diphenylsu1fone 16) ot-benzoyl-a-thiocyanoacetanilide Any of the well-known one-substituted and/or threesubstituted S-pyrazolone couplers that are incorporated in photographic emulsion layers are used to advantage in the green-sensitized layer or green-sensitized magenta color-forming unit of our photographic elements.

The 4-equipment magenta-forming couplers used according to our invention includes those having the formula:

wherein R is as described previously and R represents a group such as an alkyl group, a substituted carbamyl group, an amino group (substituted or not with one or two alkyl groups and/ or one or two aryl groups), a substituted amido group e.g., a benzamido group (substituted or not), an al-kamido group (substituted or not), etc. The R and/or R groups are advantageously substituted with any of the well-known substituent groups used in color-forming couplers including ballasting groups to render the couplers nonditfusible in hydrophilic colloid layers, and solubilizing groups.

Typical illustrative examples of 4-equiva1ent magentaforming couplers include the following:

( 1) 1-p-sec.-amylphenyl-3-n-amyl-5-pyrazolone (2) 2-cyanoacetyl-5-(p-sec.-amy1benzoylarnino) coumarone (3 Z-cyanoacetylcoumarone-S-(N-n-amy1-p-tert.-

amyl-sulfanilide) (4) Z-cyanoacetylcoumarone-5-sulfon-N-n-butylanilide (5 2-cyanoacetyl-S-benzoylamino-coumarone (6) 2-cyanoacetylcoumarone-S-sulfondirnethylarnide (7) 2-cyanoacetylcou-maronc-5-su1fon-N-methylani1ide (8 Z-cyanoacetylcoumarone-5- (N-y-phenylpropyl p-tert.-amy1sulfonanilide (9 1-p-1aurylphenyl-3 methyl-5-pyrazolone 10) 1-,8-naphthyl-3-amyl-5-pyrazolone (1 1 1-p-nitrophenyl-3-n-arnyl-5-pyrazolone 12) 1-p-phenoxyphenyl-3-n-amy1-5-pyraz0lone (13 1-phenyl-3n-amyl-5-pyrazolone 14) 1,4-phenylene bis-3-( 1-phenyl-5-pyrazolone) 15 1-phenyl-3-acetylamino-S-pyrazolone 16) 1-phenyl-3 -n-valerylamino-S-pyrazolone 17) 1-phenyl-3-chloroacety1amino-S-pyrazolone 18) l-phenyl-3-benzoylamino-S-pyrazolone 19 1-pheny1-3 (m-aminob enzoyl amino-5 -pyrazo10ne (20) 1-pheny1-3-(p-sec.-amylbenzoylamino)-5- pyrazolone 21 1-pheny1-3-diamylbenzoylamino-5-pyrazolone (22) 1-phenyl-3-fi-naphthoylarnino-S-pyrazolone (23 1-pheny1-3 -phenylcarbamylamino-5-pyrazolone (24) 1-phenyl-3-palmitylarnino-5 -pyrazolone (25 1-phenyl-3 -benzenesulfonylamino-5-pyrazolone (26) 1- (p-phenoxyphenyl -3- (p-tert-amyloxybenzoyl) amino-S-pyrazolone (27) 1- (2,4',6'-trichlorophenyl) -3-benzamido-5- pyrazolone (28) 1- 2,4',6'-tribromophenyl) -3 -pheny1acetamido- S-pyrazolone (29) 1- (2',4'-dichlorophenyl) -3- [3 (2"',4'-di-tertamylphenoxyacetamido benzamido] -5-pyrazolone (3 1- (2,4',6'-trichlorophenyl)-3- [3 (2" ,4'-ditert.-amylphenoxyacetamido benzamido pyrazolone (31) 1- (2',4',6-trichlorophenyl -3 [/3-2',4"-di-tert.-

amylphenoxy -propionarnido -5-pyrazolone (3 2) 1- (2,5-dichloro) -3- [3 (4"-tert.-amylphenoxy) benzamido] -5-pyrazolone (3 3) 1- 2',4,6'-tribromophenyl) -3- [3 (4'-tert.-

amylphenoxy) -benzan1ido] -5-pyrazolone (34) 1- (2, 5-dichlorophenyl) -3- [3 (2,4'-di-tertamylphenoxyacetamido benzamido -5-pyrazolone The 2-equivalent couplers are derived from the 4- equivalent parent couplers by replacing one of the hydrogens on the carbon in the 4-position of the pyrazolone ring with a nonchromophoric coupling off group. Examples of coupling off groups used to advantage in 2- equivalent magenta-forming couplers are the thiocyano group illustrated by the couplers in Loria US. Pat. No. 3,252,924 and the acyloxy group containing Z-equivalent magenta-forming couplers of Loria US. patent application 247,302, now U.S. Pat. No. 3,311,476. The other coupling off groups include acyloxy, aryloxy, alkoxy, arylthio, alkylthio, such as are shown in Whitmore et al. US. 3,227,550, the chlorine atom, the fluorine atom, and the sulfo group.

The 2-equivalent magenta-forming couplers used according to our invention include those having the formula:

wherein R and R are as defined previously; and Y represents a coupling otf group, such as, the thiocyano group, an acyloxy group, an aryloxy group, an alkoxy group, an alkylthio group, an arylthio group, the chlorine atom, the fluorine atom, the sulfo group, etc.

Typical illustrative examples of 2-equiva1ent magentaforming couplers include the following:

(1 1- 2,4,6-trichlorophenyl -3 4-nitro anilino -4- stearoyloxy-S-pyrazolone (2) l- 2,4,6-trichlorophenyl) -3 3- [a- 2,4-di-tertamylphenoxy -acetamido] benzamido}-4-acetoxy- 5 -pyrazolone (3) 1- 2,4,6-trichlorophenyl -3 -pentadecyl-4-thiocyano-5-pyrazolone (4) 1- (2,4,6-trichlorophenyl) -3- [3- 2,4-di-tertamylphenoxyacetamido )benzamido] -4-thiocyano-S-pyrazolone (5 1-(p-tert-butylphenoxyphenyl)-3-a-(p-tert-butyl phenoxy) -propionamido-4-thiocyano-5-pyrazolone (6) 1- 2,4,6-trichlorophenyl -3 -pentadecyl-4-sulfo- 5-pyrazolone (7) 1- (2,4,6-trichlorophenyl -3-pentadecyl-4-chloro- 5-pyrazolone (8) 1- [4- (3 ,5 -dicarboxylbenzamido) phenyl] -3-ethoxy- 4- 3-octadecylcarbarnylphenylthio) -5-pyrazolone Any of the well-known 4-equivalent phenolic and naphthoic cyan-forming couplers can be used to advantage in our red-sensitive cyan-forming layer or cyan-forming unit in our photographic materials.

The 4-equivalent cyan-forming couplers used according to our invention include those having the formulas:

wherein R represents hydrogen, an alkyl group, an aryl group, a heterocyclic group, an amino group (e.g., amino, alkylamino, arylamino, heterocyclic amino, etc.), a substituted carbonamido group (e.g., a alkylcarbonamido group, an arylcarbonamido group, and a heterocycliccarbonamido group), a substituted sulfonamido group (e.g., an alkylsulfonamido group, an arylsulfonamido group, a heterocyclicsulfonamido group, etc.), a substituted sulfamyl group (e.g., an alkylsulfamyl group, an arylsulfamyl group, a heterocyclic sulfamyl group, etc.), a substituted carbamyl group (e.g., an alkylcarbamyl group, an arylcarbamyl group, a heterocyclic carbamyl group, etc.), etc.; and R R and R each represent any of the groups represented by R and in addition the chlorine atom, an alkoxy group, etc. R R R and R are advantageously further substituted by any of the ballasting groups well-known in the art.

Typical 4-equivalent cyan-forming couplers include the following illustrative examples:

(1) 5-(p-amylphenoxybenzenesulfonamino )-1-naphthol 2) 5- (N-benZyl-N-naphthalenesulfonamino)-l-naphtho1 (3 5- (n-benzyl-N-n-valerylamino) -1naphthol 4) 5-caproylamino-1-naphthol (5) 2-chloro-5-(N-n-valeryl-N-p-isopropy1benzylamino) -1-naphtho1 6) 2-chloro-5- (p-nitrob enzoyl-fi-o-hydroxyethyb amino)-1-naphthol (7 2-ch1oro-5-palmithylaminol-naphthol 8) 2,2'-dihydroXy-5 ,5 -dibromostilbene (9) 5-diphenylethersulfonamido-l-naphthol 10) 1-hydroxy-2-(N-isomayl-N-phenyl)naphthamide 11) 1-hydroxy-2-( N-sec.-amylphenyl)naphthamide 12) 8-hydroxy-1-a-naphthoyl-1,2,3,4-tetrahydroquinoline 13) 1-naphthol-2-carboxylic-a-naphthalide l4) l-naphtho1-5-sulfo-cyclohexylamide 15) 5-phenoxyacetamino-l-naphthol 16) 5-fi-phenylpropionylamino-l-naphthol 17) Monochlor-S- (N-y-phenylpropyl-N-p-sec.-amylbenzoylamino)-1-naphthol 18) 2-acetylamino-5-methylphenol l9) 2-benzoylamino-3,S-dimethylphenol (20) 2a- (p-tert.-amylphenoxy) -n-butyrylamino-5- methylphenol 21) l-hydroxy-Z- [a- 2,4-di-tert.-amylphenoxy) -n-buty1] naphthamide (22) 2- (4"-tert-amyl-3 '-phenoxybenzoylarnino -3,5-

dimethyll-phenol (23 2(4-phenoxybenzoylamino) phenol 24) 2(4'-tert.-amyl-3 '-phenoxybenzoylamino phenol (25 Z-[oc- (4'-tert.-butylphenoxy)propionylamino] phenol (26) 2- [N-methyl-N-(4"-tert.-amyl-3'-phenoxybenzoylamino) ]phenol 27) 2- (4"-tert.-amyl-3 -phenoxybenzoylamino)-3- methyll-phenol (28) 2-(4"-tert.-amyl-3-phenoxybenzoylamino)-6- methyl-l-phenol (29) 2-( 4"-tert.-amyl-3 '-phenoxybenzoylamino -3 ,6-

dimethylphenol (3 2,6-di (4"-tert.-amyl-3 '-phenoxybenzoylamino -1- phenol (3 l Z-oc- (4-tert.-amylphenoxy)butyrylamino-l-phenol (32) 2(4-tert.-amyl-3'-phenoxybenzoylamino)-3,5-

dirnethyl-l-phenol (33) 2- oc- (4'-tert.-amylphenoxy -u-butyrylamino] methyl-l-phenol (3 4) 2 4"-tert.-amyl-3 '-phenoxybenzoylamino -4- chloro-l-phenol (35) 3- oc- 4'-tert.-amylphenoxy) -n-butyrylamino] -6- chlorophenol (36) 3-(4"-tert.-amyl-3'-phenoxybenzoylamino)phenol (37) 2-[u-(4'-tert.-amylphenoxy)n-butyrylarnino]-6- chlorophenol (3 8) 3- a- 4-tert.-amylphenoxy) -n-butyrylamino] -5- chlorophenol (39) 3 [a- 4-tert.amylphenoxy -n-butyryla1nino] -2- chlorophenol (40) 2-a-(4'-tert.-amylphenoxybutyrylamino)-5-chlorophenol (41) 2- (4"-tert.-arnyl-3 '-phenoxybenzoylamino) -3- chlorophenol (42) S-benzene sulfonamino-l-naphthol (43) 2-chloro-5-benzenesulfonamino-l-naphthol (44) 2-chloro-5-(p-toluenesulfonamino)-l-naphthol (45 5-( 1 ,2,3,4-tetrahydronaphthalene-6-sulfamino) l-naphthol (46) 2-chloro-5-(4-bromodiphenyl-4-sulfonamino)-lnaphthol (47) 5-(quinoline-S-sulfamino)-1-naphthol Any of the well-known 2-equivalent cyan-forming couplers known in the art for incorporation in photographic layers may be used to advantage. Usually the 2-equivalent couplers are derived from the corresponding 4-equivalent couplers by substituting a nonchromophoric coupling oft" group on the carbon in the 4-position of the phenolic or naphthoic ring. Included among the coupling off groups are the acyloxy group illustrated by the 4-acyloxyphenols and 4-acyloxynaphthols of Loria U.S. Patent application 247,302, filed Dec. 26, 1962, now U.S. Pat. 3,311,-

476, the cyclooxy group illustrated by the 4-cyclooxy naphthols of Loria U.S. patent application 483,807, filed Aug. 30, 1965, the thiocyano group illustrated by the 4- thiophenols and 4-thionaphthols of Loria U.S. Pat. 3,253,

294, the cyclic irnido groups as illustrated by the 4-cyclic imido derivatives of l-hydrogen-2-naphtharnides of Loria U.S. patent application 504,994, now U.S. Pat. 3,458,315,

the chlorine atom as illustrated in the 4-chlorophenols of Weissberger U.S. Pat. 2,423,730, the alkoxy group and the arylthio group as illustrated by the 4-alkoxynaphthols and 4-arylthiophenols (and naphthols) of Whitmore et al. U.S. Pat. 3,227,550, the sulfo group as in 4-sulfophenols and 4-sulfonaphthols, etc.

The 2-equivalent cyan-forming couplers used according to our invention include those having the formulas:

vn on Rs R2 and (VIII) 11 wherein R R R and R are as defined previously; Y represents the groups previously defined for Y but does not represent an aryloxy group; Y represents the groups previously defined for Y and also includes a cyclic i-mido group (e.g., a maleimido group, a succini-mido group, a 1,2-dicarboximido group, a phthalimido group, etc.).

Typical examples of 2-equivalent cyan-forming couplers include the following illustrative couplers:

(1 1-hydroxy-4-stear0yloxy-2-naphthoic acid (2) l-hydroxy-4-acetoxy-N-[6-(2,4-di-tert amylphenoxy) butyl] -2-naphthamide (3) 1-hydroxy-4-acetoxy-N-octadecyl-3',5'-dicarboxy- Z-naphthanilide (4) 1-hydroxy-4-thiocyano-N-[a-2,4-di-tert-arnylphenoxy) butyl] -2-naphthamide (5 1-hydroxy-4- (pentafluorophenoxy -N-{B-{4- [m- 2,

4-di-tert-amylphenoxy acetamido] phenyl}ethy 2-naphthamide (6) l-hydroxy-4- 4-nitrophenoxy -N- 8-2,4-di-tertamylphenoxy) butyl] -2-naphthamide (7 1-hydroxy-4- (4-chlorophenoxy -2-tetradecyloxy- 2-naphthanilide (8 1-hydroXy-4-phthalimido-N- [6 (2,4-di-tert-amylphenoxy) butyl] -2-naphthamide (9) 1-hydroxy-4- dodecenylsuccinimido -N- 54 2,4-ditert-amylphenoxy) butyl] -2-naphthamide 10) 2-a(p-tertamylphenoxy) -n-butyrylamino-4- chloro-5 -methylphenol 1 1 l-hydroxy-4-phenylthio-N- 6- (2,4-di-tert-amylphenoxybutyl] -2-naphthamide 12) 1-hydroxy-3,5'-dicarboxymethoxy-4-dodecyloxy- Z-naphthanilide Usually the couplers are used to advantage in our materials are ballasted to make them nondilfusible in the silver halide emulsions in which they are incorporated. The couplers utilized in our invention can be dispersed in a high boiling, crystalloidal compound which can be used as a vehicle for incorporating the coupler in the photographic emulsion according to methods well-known in the art. Various other known methods of incorporating the color-forming couplers in our element may also be utilized. For example, the low solvent dispersion described in Fierke U.S. Pat. 2,801,107 are used to advantage; or the couplers may be dispersed in natural resin-type solvents as described in Materinz US. Pat. 2,284,879; or the couplers may be dissolved in monomeric solution which is then polymerized in the presence of gelatin to produce dispersions of the coupler in the polymer as described in U.S. Pat. 2,825,382. Alternately, the color-forming couplers can be of the fat-tail variety, that is, the Fischer type which have solubilizing groups on them which render them soluble in alkaline solution.

Couplers that form diffusible dyes may also be used in our elements wherein interest is indicated in the transfer of the color image to a contiguous receiver sheet as is described in Whitmore et al. U.S. Pat. 3,227,550. Our color-forming units used to advantage in the elements of U.S. Pa-t. 3,227,550 would use nondifiusible 2-equivalent couplers such as are shown in this reference along with the appropriate 4-equivalent parent coupler of the reference in order to produce ditfusible dye images for transfer. The elements described herein are also useful in color transfer processes wherein a dye, a developer or a coupler are transferred to a receiver layer or sheet.

In addition to the hydrophilic colloid binder materials mentioned previously, polyvinyl pyrolidone and mixtures of it with the other hydrophilic colloids are used to ad vantage in our emulsion layers. In addition to the addenda already described, our emulsions also advantageously contain any of the well-known stabilizers; antifoggants; speed increasing materials, such as polyalkylene oxides, onium salts and thioethers; plasticizers; coating aids, such as anionic, nonionic and amphoteric surface active compounds and the like. In addition to the chemical sensitization of our hydrophil-ic colloid silver halide emulsions described above, our emulsions are also advantageously reduction sensitized with reducing agents.

The various layers of the photographic elements of our invention are advantageously hardened with any of the known hardeners including, for example, aldehyde hardeners, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides, such as oxystarch, oxyplant gums and the like.

The photographic layers described herein are advantageously coated on a wide variety of supports. Typical supports included those generally employed in photographic elements such as cellulose nitrate, cellulose acetate, polyvinyl acetal, polystyrene, polycarbonate, polyethylene terephthalate and related films or resinous materials.

As has been mentioned previously, the color-forming units of our invention comprise two-differentially sensitive hydrophilic colloid silver halide emulsion layers, that is, one emulsion layer is sensitized to a higher speed than the other with the higher speed emulsion containing the 4-equivalent coupler and the lower speed emulsion containing the 2-equivalent coupler. Although the lower speed emulsion may be located so that the exposing light reaches it before reaching the faster emulsion layer, it is more advantageous and preferable to have the faster emulsion layer coated so that the exposing light reaches it first. The ratio of the faster to the slower silver halide in our color-forming units may be varied over wide ranges; for example, an operable ratio of the faster to slower silver halide is in the range from about 1: about 99 to about 99: about 1 with a preferred ratio in the range from about 25: about 75 to about 90: about 10. The coating rates for the silver halide can be varied widely and will depend upon the particular couplers and v the desired results. As has been mentioned before, 4-

equivalent couplers require the reduction of 4 moles of silver halide to produce one mole of image dye while the 2-equivalent couplers require the reduction of only 2 moles of silver halide to produce one. mole of image dye. Usually the combined 4- and Z-equivalent coupler coating rates in a given color-forming unit of our invention is in the operable range of from about 25 to about 300 mg. per sq. ft. with a preferred value in the range from about 40 to about 150 mg. per sq. ft. Similarly the combined silver in the faster and slower emulsion layers of one of our color-forming units falls within the same ranges as specified for the combined couplers.

As has been mentioned before, our elements contain at least one of our color-forming units. The greatest advantage is derived from using one, of our color-forming units positioned in the photographic element where the exposing light first strikes the element. Additional improvement is also obtained by using the second color-forming unit of our invention in the photographic element which would be exposed by light transmitted through the first color-forming unit. A third color-forming unit of our invention is also advantageously used in our photographic elements. Obviously the arrangement of the color-forming unit(s) and the orientation of the two emulsion layers within the color-forming units in a photographic element will depend upon whether it is designed for exposure through a transparent support or through the side of the coatings away from the support.

Our photographic elements are advantageously color processed after exposure in conventional color processes used for photographic elements containing incorporated couplers. In the reversal processes the film is first developed with a black-and-White negative developer solution, then following exposure to white light or treatment in a nucleating bath is given color development in an aqueous alkali solution containing a primary aromatic amine color developing agent. After color development, the photographic material is treated with a ferricyanide bleach solution followed by a thiosulfate fixing bath to 12 remove the silver image and residual silver halide, thus leaving the dye images.

Especially useful color developing agents used for color developing our photographic elements are primary phenylene diamines and their derivatives, such as,

( l N,N-dimethyl-p-phenylenediamine,

(2) N,N-diethyl-p-phenylenediamine,

(3 N-carbamidomethyl-N-methyl-p-phenylenediamine (4) N-carbamidomethyl-N-tetrahydrofurfuryl-2- methyl-p-phenylenediamine,

(5) N-ethyl-N-carboxymethyl-Z-methyl-p-phenylenediamine,

(6) N-carbamidomethyl-N-ethyl-Z-methyl-p-phenylene diamine,

(7) N-ethyl-N-tetrahydrofurfuryl-Z-methyl-p-aminophenol,

( 8) 3-acetylamino-4 aminodimethylaniline,

(9) N-ethyl-N-fl-methanesulfonamidoethyl-4-aminoaniline (10) N-ethyl-N-[i-methanesulfonamidoethyl-3-methyl- 4-arninoaniline,

(11) the sodium salt of N-methyl-N-,B-sulfoethyl-pphenylenediamine, etc.

The following typical examples will still further illustrate our invention by showing how our color-forming units are used in our multicolor elements to provide the technical advances of our invention. Example 1, Coating B shows how the light-sensitive layers of one of our yellow-forming units is used as the top or outermost image-forming stratum (identified as Layers l and 2) in a color element. The higher speed gelatino-silver halide emulsions used in our Examples 1 through 6 are relatively coarse grain gelatino-silver bromoiodide emulsions while the lower speed gelatino-silver halide emulsions used in these examples are finer grain emulsions, both of which are made as described by Trivelli and Smith, Phot. Journal, vol. 79, 330 (1939).

EXAMPLE 1 Two coatings, Coatings A and B, are prepared with the following basic structure:

Layer 1-Blue-sensitive emulsion containing a yellowforming coupler Layer 2Slower speed blue-sensitive emulsion containing a yellow-forming coupler Layer 3-Yellow filter layer Layer 4-Green-sensitive emulsion containing a magentaforming coupler Layer 5Slower speed green-sensitive emulsion containing a magenta-forming coupler Layer 6Red-sensitive emulsion containing a cyan-forming coupler Layer 7--Slower speed red-sensitive emulsion containing a cyan-forming coupler Layer 8Support Layers 3 through 8 are identical in both Coatings A and B. Layers 4 and 5 in these coatings contain a 4- equivalent pyrazolone coupler for the formation of the magenta image as described in column 17, lines 56 and 57 of Graham et a1. U.S. Pat. 3,046,129 and layers 6 and 7 contain a Z-equivalent phenolic coupler for the formation of the cyan image as described in column 15, lines 74 and 75 of U.S. Pat. 3,046,129. Layers 1 and 2 in Coating A contain 75 milligrams per sq. ft.

of a 2-equivalent alpha-cyclooxy yellow-forming coupler No. 25 of Loria French Pat. 1,411,384. Both of these layers contain a silver coverage of 40 mg. per

sq. ft. Layer 1 in Coating B contains mg. per sq. ft.

of the 4-equivalent yellow-forming coupler No. 10 of Weissberger et a1. U.S. Pat. 3,265,506, and is coated to yield a silver coverage of 80 mg. per sq. ft. Layer 2 in Coating B contains 75 mg. per sq. ft. of the 2-equivalent yellow-forming coupler N0. 25 of Loria French Pat. 1,411,384 and is coated to yield 40 mg. of silver per sq. ft. Each of these coatings is then exposed to blue light on an intensity scale sensitometer using a #47 B Wratten filter and is processed in the Kodak Ektachrome (Eastman Kodak Companys registered trademarks) commercial film color reversal process (ECO-2 process). Coating B of our invention which contains more silver (than Coating A), exhibits a relative speed of 182 compared to a relative speed of 100 for Coating A with no appreciable loss in sharpness compared to Coating A. Coating B is also noted to have much better sharpness than a similar coating (Coating C) in which both yellow layers contain a 4-equivalent coupler necessitating the use of a higher silver concentration than in Coating B.

The ECO-2 process used in our examples is described in Abridged Operating Specifications for ECO-2 Process, dated July 1964, and supplied by Eastman Kodak Co., Motion Picture and Education Marketing Division to the Professional Film Processing Laboratories in the United States.

I EXAMPLE 2 Multicolor element Coating D is prepared like Coating B of Example 1 but using another blue-sensitive yellow-forming unit of our invention in which an equimolar amount of Coupler No. 11 in Loria Canadian Pat. 735,836 is used as the 2-equivalent coupler in Layer 2 in place of the coupler used in Layer 2 of Coating B and an equirnolar amount of Coupler No. XIV in McCrossen et al. U.S. 2,875,057 is used in Layer 1 in place of the coupler used in Layer 1 of Coating B. Upon image-exposure and processing as described in Example 1, the good photographic speed and improved image sharpness obtained, again illustrate the substantial technical advance provided by our invention.

EXAMPLE 3 Multicolor element Coating E is prepared like Coating B of Example 1 but using an equirnolar amount of the 2-equivalent yellow-forming coupler described as coupler No. of Loria et a1. U.S. Pat. 3,277,155 in Layer 2 in place of the coupler used in Layer 2 of Coating B, and using in Layer 1 an equimolar amount of the: 4-equivalent yellow-forming coupler described as Coupler No. of Weissbcrger et al. U.S. Pat. 3,265,506 in place of the coupler used in Layer 1 of Coating B. Upon image-exposure and processing as described in Example 1, the good photographic speed and improved image sharpness obtained, again illustrate the substantial technical advance provided by our invention.

Similar results are obtained when Coating B of Example l is repeated using other blue-sensitive yellow-forming units of our invention in which still other 4-equivalent yellow-forming couplers of Formula I and still other Z-equivalent yellow-forming couplers of Formula II are used in place of the couplers used in Layers 1 and 2 respectively of Coating B in the above and other hydrophilic colloid silver halide emulsions of our invention in which the ratio of silver in the fast emulsion to silver in the slower emulsion of our invention is in the range from about 1:99 to about 99:1.

Examples 4 and 5 illustrate our multicolor elements that have both a yellow-forming unit and a magentaforming unit of our invention.

EXAMPLE 4 Multicolor element Coating F is prepared like Coating B of Example 1 but using in place of the Layer 5 of Coating B, a green-sensitized gelatino silver bromoiodide emulsion layer containing 75 mg. per sq. ft. of the Z-equivalent magenta-forming coupler described as Coupled No. 3 in Loria U.S. patent application 247,302, filed Dec. 26, 1962, now U.S. Pat. 3,311,476, coated to yield a silver coverage of 40 mg. per sq. ft., and using in place of Layer 4 of Coating B, a green-sensitized gelatino-silver bromoiodide emulsion layer (having a speed that is .7 log exposure faster than the emulsion layer 5 of Coating F) said layer containing mg. per sq. ft. of the 4-equivalent coupler shown in Graham et al. U.S. Pat. 3,046,129, column 17, lines 56 and 57 coated to give a silver coverage of 80 mg. per sq. ft. Upon image-exposure to blue light as in Example 1 and to green light and processing as described in Example l, the good photographic speed and improved image sharpness obtained, again illustrate the substantial technical advance provided by our invention.

EXAMPLE 5 Similar results are obtained when Example 4 is repeated with Coating G in which an equimolar amount of the Z-equivalent magenta-forming coupler described as Coupler No. 2 in Loria U.S. patent application 247,302, now U.S. Pat. 3,311,476 is used in Layer 5 in place of the coupler used in Layer 5 of Coating F, and an equimolar amount of the 4-equivalent magentaforming coupler described as Coupler No. 5 in Tuite U.S. Pat. 3,152,896 is used in Layer 4 in place of the coupler in Layer 4 of Coating F.

The following example illustrates a typical multicolor element of our invention in which a yellow-forming unit, a magenta-forming unit and a cyan-forming unit of our invention are used.

EXAMPLE 6 Multicolor Coating H is prepared like Coating F but in which Layer 7 of Coating F is replaced by a redsensitized gelatino silver bromoiodide emulsion containing 75 mg. per sq. ft. of the 2-equivalent cyan-forming coupler described by Graham et al. in U.S. Pat. 3,046,129, column 15, lines 74 and 75, that is coated to yield a silver coverage of 40 mg. per sq. ft. and Layer 6 of Coating F is replaced by a red-sensitized gelatino-silver bromoiodide emulsion layer (having a speed that is .7 log exposure faster than the emulsion in Layer 6) said layer containing 80 mg. per sq. ft. of the corresponding 4- equivalent coupler (i.e., the coupler with no chlorine atom substituted on the carbon in the 4-position of the phenol ring) that is coated to yield a silver coverage of 80 mg. per sq. ft. Upon image-exposure and processing as described in Example 5, the good photographic speed and improved image sharpness obtained, again illustrate the substantial technical advance provided by our invention.

Similarly, other multicolor elements made according to our invention in which other of our color-forming units containing other hydrophilic colloid-silver halide emulsions, other 4-equivalent and other 2-equivalent couplers, as well as other addenda can be shown to provide both improved photographic speed and improved image sharpness.

It is to be understood that these technical advances are also obtained by making and using other multicolor elements of our invention which have the color-forming units arranged differently than shown in the above examplcs provided that one of our novel color-forming units is located so that exposing light passing through it subsequently exposes the light-sensitive layers recording light of at least one other primary color of the spectrum.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be eifected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. In a multilayer, multicolor photographic element containing incorporated color-image-forming couplers, the said element comprising a support coated in succession with dilferently color-sensitive color-forming hydrophilic colloid-silver halide emulsion strata such that at least the silver halide emulsion stratum which is first to receive light during image exposure is comprised of a color-forming unit, said unit comprising:

15 (1) a first hydrophilic colloid layer containing a silver halide emulsion sensitive to one primary color region of the spectrum, and (2) a second hydrophilic colloid layer containing a silver halide emulsion sensitive to substantially the same region of the spectrum as the silver halide in the said first layer and having a higher photographic speed than the silver halide in the said first layer, said second layer being coated so that is receives light during image exposure before the said first hydrophilic colloid layer, the improvement comprising the incorporation in at least one color-forming unit of an appropriate 4-equivalent color-forming coupler in the faster of the said layers and an appropriate Z-equivalent color-forming coupler in the other said layer in the color-forming unit such that the said 4-equivalent and 2-equivalent couplers form dyes in substantially the same primary color region of the spectrum, and the 2-equivalent coupler is substantially colorless.

2. In a multilayer, multicolor photographic element containing incorporated color-image-forming couplers, said element comprising a support coated in succession with differently color-sensitive color-forming units, each unit comprising two hydrophilic colloid silver halide emulsion layers such that the said emulsion layer that is farthest from the said support in each unit is a higher speed emulsion than the said emulsion layer that is closest to the support in each unit, the improvement comprising the incorporation in at least the outermost of said color- -forming units of a 4-equivalent coupler in the layer of the said unit that is farthest from the said support and a substantially colorless 2-equivalent coupler in the layer of the said unit that is closest to the said support.

3. In a multilayer, multicolor photographic element containing incorporated color-image-forming couplers, said element comprising a support coated in succession with differently color-sensitive color-forming units, each unit comprising two hydrophilic colloid-silver halide emulsion layers such that the said emulsion layer that is farthest from the said support in each unit is a higher speed emulsion than the emulsion layer that is closest to the support in each unit, the improvement comprising the incorporation in an outermost blue-sensitive yellow-forming unit of a 4-equivalent yellow-forming coupler in the layer of the blue-sensitive unit farthest from the said support and a substantially colorless Z-equivalent yellow-forming coupler in the said blue-sensitive layer closest to the said support.

4. An improved multilayer, multicolor photographic element of claim 3 in which the said 4-equivalent yellowformin-g coupler is an open-chain active methylene containing yellow-forming coupler and the said 2-equivalent yellow-forming coupler is an open-chain active methylene containing yellow-forming coupler having one of the two hydrogens on the said active methylene group replaced with a coupling ofi group.

5. An improved photographic element of claim 3 in which the said 4-equivalent yellow-forming coupler is an open-chain ketomethylene coupler and the said 2- equivalent yellow-forming coupler is an open-chain ketomethylene yellow-forming coupler having a monovalent coupling off group selected from the class consisting. of the fluorine atom, the chlorine atom, an acyloxy group, a cyclooxy group, an arylthio group, an alkylthio group, the thiocyano group, and the sulfo group.

6. An improved photographic element of claim 3 in which the blue-sensitive yellow-forming unit contains gelatino-silver bromoiodide emulsions, the said 4-equivalent yellow-forming coupler is an open-chain ketomethylene yellow-forming coupler and the said Z-equivalent yellow-forming coupler is a benzoyl acetanilide coupler having one of the two hydrogen atoms attached to the alpha carbon atom replaced by a monovalent coupling ofl group selected from the class consisting of the fluorine atom, the chlorine atom, an acyloxy group, a cyclooxy 16 group, an arylthio group, an alkylthio group, the thiocyano group and the sulfo group.

7. An improved photographic element of claim 3 in which the blue-sensitive yellow-forming unit contains gelatino-silver bromoiodide emulsions, the said 4-equivalent yellow-forming coupler is an open-chain ketomethylene yellow-forming coupler and the said Z-equivalent yellowforming coupler is a pivalyl acetanilide coupler having one of the two hydrogen atoms attached to the alpha carbon atom replaced by a monovalent coupling oif group selected from the class consisting of the fluoring atom, the chlorine atom, an acyloxy group, a cyclooxy group, an arylthio group, an alkylthio group, the thiocyano group and the sufo group.

8. An improved photographic element of claim 3 in which the blue-sensitive yellow-forming unit contains gelatino silver bromoiodide emulsions, the said 4-equivalent coupler is an tx-pivalylacetanilide yellow-forming coupler and in which the 2-equivalent coupler is an alphafluoro a-pivolylacetanilide coupler.

9. An improved photographic element of claim 3 in which the blue-sensitive yellow-forming unit contains gelatino silver bromoiodide emulsions, the said 4-equivalent yellow-forming coupler is an open-chain benzoyl acetanilide yellow-forming coupler and the said 2-equivalent coupler is an alphaacyloxy benzoyl acetanilide coupler.

10. In a multilayer, multicolor photographic element containing incorporated color-image forming couplers, said element comprising a support coated in succession with differently color sensitive color-forming units, each unit comprising two hydrophilic colloid-silver halide emulsion layers such that the said emulsion layer that is farthest from the said support in each unit is a higher speed emulsion than the emulsion layer that is closest to: the support in each unit, the improvement comprising:

(1) the incorporation in the outermost blue-sensitive yellow-forming unit of a 4-equivalent yellow forming coupler in the layer of the blue-sensitive unit farthest from the said support and a substantially colorless 2-equivalent yellow-forming coupler in the said bluesensitive layer closest to the said support,

(2) in the green-sensitized magenta-forming unit coated under the said yellow-forming unit, the incorporation of a 4-equivalent S-pyrazolone magenta-forming coupler in the layer of the magenta-forming unit farthest from the said support and a 2-equivalent 5-pyrazolone magenta-forming coupler in the layer of the ma genta-forming unit closest to the said support.

11 An improved photographic element of claim 10 in which the 2-equivalent S-pyrazolone coupler is. substituted on the carbon in the 4-position with a coupling ofi group selected from the class consisting of the chlorine atom, the fluorine atom, an acyloxy group, an aryloxy group, an alkoxy group, an arylthio group, an alkylthio group, the thiocyano group and the sulfo group.

12 In an improved photographic element of claim 10 in which the Z-equivalent S-pyrazolone coupler is a 4-acyloxy S-pyrazolone coupler.

13. In a multilayer, multicolor photographic element containing incorporated color-image forming couplers, said element comprising a support coated in succession with differently color sensitive color-forming units, each unit comprising two hydrophilic colloid-silver halide emulsion layers such that the said emulsion layer that is farthest from the said support in each unit is a higher speed emulsion than the emulsion layer that is closest to the said support in each unit, such that one of the said color forming units is a blue-sensitive yello wforming unit, another color forming unit is a green-sensitized magentaforming unit, and a third color-forming unit is a redsensitied cyan-forming unit, the improvement comprising:

(1) the incorporation in the yellow-forming unit of a 4-equivalent yellow-forming coupler in the layer of said unit farthest from the said support and a sub- 17 stantially colorless 2-equivalent yellow-forming coupler in the layer of the yellow-forming unit closest to the said support,

(2) the incorporation in the green-sensitized magenta- :forming unit of a 4-equivalent magenta-forming coupler in the layer of the magenta-forming unit farthest from the said support and a substantially colorless 2-equivalent magenta-forming coupler in the magenta-forming layer closest to the said support, and

(3) the incorporation in the said red-sensitized cyanforming unit of a 4-equivalent cyan-forming coupler in the layer farthest from the said support and a substantially colorless 2-equivalent cyan-forming coupler in the layer of the cyan forming unit closest to the said support.

14. An improved photographic element of claim 13 in which the 4-equivalent yellow forming coupler is an openchain benzoylacetanilide, the 2-equivalent yellow-forming coupler is an alpha-acyloxybenzoylacetanilide coupler, the 4-equivalent magenta-forming coupler is a 5-py1'azolone coupler, the 2-equivalent magenta-forming coupler is a 4-acyloxy-5-pyrazolone coupler, the 4-equivalent cyanforming coupler is a phenolic coupler and the 2-equivalent cyan-forming coupler is a 4-chloro substituted phenolic coupler.

References Cited UNITED STATES PATENTS 3,419,391 12/1968 Young 96-100 NORMAN G. TORCHIN, Primary Examiner J. R. HIGHTOWER, Assistant Examiner U .5. Cl. X.R. 96-100